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• C++/C extract specific frame from video file

  21 novembre 2023, par CoXier

  As titles says, I want to extract certain frame from video file. Now I can use FFmpeg command line tool to do that.

  



  ffmpeg -i in_video.avi -vf "select=gte(n\,100)" -vframes 1 out_img.png


  



  However I can not use FFmpeg command line tool directly. So can I extract specific frame in C/C++ ?

  


• A Better Process Runner

  1er janvier 2011, par Multimedia Mike — Python

  I was recently processing a huge corpus of data. It went like this : For each file in a large set, run 'cmdline-tool <file>', capture the output and log results to a database, including whether the tool crashed. I wrote it in Python. I have done this exact type of the thing enough times in Python that I’m starting to notice a pattern.

  Every time I start writing such a program, I always begin with using Python’s commands module because it’s the easiest thing to do. Then I always have to abandon the module when I remember the hard way that whatever ’cmdline-tool’ is, it might run errant and try to execute forever. That’s when I import (rather, copy over) my process runner from FATE, the one that is able to kill a process after it has been running too long. I have used this module enough times that I wonder if I should spin it off into a new Python module.

  Or maybe I’m going about this the wrong way. Perhaps when the data set reaches a certain size, I’m really supposed to throw it on some kind of distributed cluster rather than task it to a Python script (a multithreaded one, to be sure, but one that runs on a single machine). Running the job on a distributed architecture wouldn’t obviate the need for such early termination. But hopefully, such architectures already have that functionality built in. It’s something to research in the new year.

  I guess there are also process limits, enforced by the shell. I don’t think I have ever gotten those to work correctly, though.

• Chromium Build Failed on Windows:D3D Compiler DLL (\third_party\angle\src)

  31 mars 2016, par Vish

  I have followed same step mentioned in this question. Few extra flag I have set get propriety FFMPEG codec. Its failing every time, with following logs.

  [233/19712] ACTION Copying D3D Compiler DLL...
  
  FAILED: F:\Chrome\depot_tools\python276_bin\python.exe gyp-win-tool action-wrapper environment.x86 copy_compiler_dll_target_copy_dll_a30e198148542d4bce19a5c818c6884f..rsp ..\..\third_party\angle\src
  
  [233/19712] CC obj\third_party\icu\source\stubdata\icuuc.stubdata.obj
  
  ninja: build stopped: subcommand failed.

  For FFMPEG using following set command :

  set GYP_DEFINES=branding=Chromium buildtype=Official component=shared_library disable_nacl=1 enable_automation=0 enable_captive_portal_detection=0 enable_google_now=0 enable_hidpi=0 fastbuild=1 ffmpeg_branding=Chrome incremental_chrome_dll=0 proprietary_codecs=1 remoting=0

  My System Information Details :

  Windows 10 64 Bit 8 GB RAM. Trail Version of Visual Studio 2015
  Installed, but now it is expired. Now I have installed Community
  Version 2013 update 4.

  Does it effect both version effect the execution ? Checked in path, its using Window Kit 8.1. What other part should I check for successful execution ?